OPC UA使用opc.uafx.advanced开发客户端、服务端

        OPC在自动化行业使用很广泛，好一点的PLC支持OPC协议，比如国内的汇川、禾川PLC对应高端的PLC都支持OPC UA协议，低端一点的则使用Modbus和上位机通讯，或者TCP自定义格式。相比于modbus协议，OPC不用确定寄存器地址，可以主动查询到OPC服务端对应的所有变量及属性，以object为根节点。

        OPC在C#中开发使用客户端方法很多，可以自行搜索，如果OpcUaHelper等。作为服务端，可以使用github上OPC开源代码，也可以使用如下介绍的opc.uafx.advanced（使用简单）。

        更多OPC介绍，参考我之前我的内容。

参考网站：OPC UA SDK for .NET - Client / Server in C# VB.NET schnell und einfach

NuGet添加引用：opc.uafx.advanced

服务端示例代码：https://docs.traeger.en/de/software/sdk/opc-ua/net/server.development.guide

客户端示例代码：Client Development Guide & Tutorial - TRAEGER Docs

客户端

using System;
using System.Threading;
 
using Opc.UaFx.Client;
 
public class Program 
{
  public static void Main()
  {
    using (var client = new OpcClient("opc.tcp://localhost:4840")) {
      client.Connect();

      while (true) {
        var temperature = client.ReadNode("ns=2;s=Temperature");
        Console.WriteLine("Current Temperature is {0} °C", temperature);
 
        Thread.Sleep(1000);
      }
    }
  }
}

服务端

using System.Threading;

using Opc.UaFx;
using Opc.UaFx.Server;

class Program
{
  public static void Main()
  {
    var node = new OpcDataVariableNode("Temperature", 100.0);

    using (var server = new OpcServer("opc.tcp://localhost:4840/", node)) {      
      server.Start();

      while (true) {
        if (node.Value == 110)
            node.Value = 100;
        else
            node.Value++;

        node.ApplyChanges(server.SystemContext);
        Thread.Sleep(1000);
      }
    }
  }
}

打开服务端和客户端的示例代码

using Opc.UaFx;
using Opc.UaFx.Client;
using Opc.UaFx.Server;

// Define the root node of server
var machineNode = new OpcObjectNode("Machine");
// Declear a variable Hello world like very started.
var messageNode = new OpcDataVariableNode("Message", "Hello World!");

// It's a variable set to false.
bool variableValue = false;

// bind the variable to root.
var isRunningNode = new OpcDataVariableNode(
    machineNode,
    "IsRunning",
    value: variableValue);

// bind another one in case.
var jobNode = new OpcObjectNode(
    machineNode,
    "Job",
    new OpcDataVariableNode("Cancel", false),
    new OpcDataVariableNode("State", -1));

// New a opc server. Make sure tcp port 4840 haven't been used before
using var server = new OpcServer(
    "opc.tcp://localhost:4840/", machineNode, messageNode);

// Start it
server.Start();

// Wait a second
Thread.Sleep(1000);
//while (true) ;

// New a client to connect to 4840
using var client = new OpcClient("opc.tcp://localhost:4840/");

// Connect anyway
client.Connect();

// Print the variable value. It should be false here.
Console.WriteLine(client.ReadNode("ns=2;s=Machine/IsRunning"));

// Write some values.
OpcStatusCollection results = client.WriteNodes(
    new OpcWriteNode("ns=2;s=Machine/Job/Cancel", true),
    new OpcWriteNode("ns=2;s=Machine/Job/State", 0));
// Print them.
Console.WriteLine(client.ReadNode("ns=2;s=Machine/Job/Cancel"));
Console.WriteLine(client.ReadNode("ns=2;s=Machine/Job/State"));